Half marathon training plan (21K)
The half marathon is the big endurance challenge for many runners: the distance asks for patience, progressive long runs and a well-chosen race pace.
Who is it for?
For anyone who already runs 10K comfortably and wants to move up, and for those looking to improve their 21K time.
How much time you need
From a 10K base, 10 to 14 weeks lets you arrive calmly. The long run grows gradually to around 18–20 km, with lighter weeks mixed in so you absorb the load.
The typical week
Two easy runs, one quality session (tempo, or long intervals of 2,000–3,000 m at goal pace) and the long run. Some long runs can finish with the last kilometers at race pace to practice running tired.
Race pace and fueling
Pick a pace you can hold for 21 km and start patiently. Test in your long runs what you'll drink or eat on race day: what isn't tried in training isn't used in competition.
Common mistakes
- Running long runs at too demanding a pace.
- Adding kilometers all at once in the final weeks.
- Not practicing hydration and fueling in training.
- Going out too fast in the first 5 km.
Frequently asked questions
How many times should I run 21 km before the race?
You don't need to run the full 21 km beforehand: with 18–20 km long runs and good progression you'll arrive ready. Race day adds the rest.
What pace suits my first half marathon?
One that feels comfortable until kilometer 15; whatever is left is for the finish. With a personalized plan it's calculated from your recent times.